Wheeled vacuum cleaner heads for use in cleaning sediments and particulate matter from the submerged surfaces of swimming pools, spas and the like have been known for several decades and are now quite well known. Such devices first appeared as rigid articles having wheels for supporting an elongate platform-like cleaner body a selected distance above a pool surface to be cleaned. Those early cleaner heads, like those commonly used today, defined a hole through a central part of the body into a short upstanding tube which was configured to snugly receive and retain, usually about the outer surface of the tube, an end of a water suction hose. The other end of the hose was connected, directly or indirectly, to the suction port of a pump forming part of a circulation system for circulating water from the pool, through a filter, and a back to the pool. Such early cleaners, like those commonly used today, also included a mechanism for connecting to the cleaner body, adjacent the upstanding tube, a lower end of a pole usable by a person standing outside the pool adjacent its rim to maneuver the cleaner head as desired about on the submerged pool surface. Water flowing from the pool into the space between the cleaner head and the pool surface and into the hole in the body entrained in it sediment and particulate matter and carried it up through the suction hose for removal from the flowing water by the pool filter.
The early forms of wheeled pool vacuum cleaner heads were rigid. In about 1966, a flexible vacuum head according to U.S. Pat. No. 3,273,188 became commercially available and was followed by other forms of flexible heads. Flexible vacuum heads have gained wide, if not predominant, acceptance for several reasons, notably their ability to bend along their length to conform to curved portions of the submerged surfaces of swimming pools and spas. However, in one important respect, the flexible wheeled vacuum heads were like their rigid ancestors; they supported the cleaner head body in spaced relation to the surface being cleaned so that ingress of water into the space between the head and the pool surface occurred at all points around the perimeter of the space. In these rigid and flexible heads, some parts of the space perimeter were closer to the suction port of the head than were other parts of the space's perimeter, and so the velocity of water flow through those former parts of the perimeter and to the suction port was greater than the flow velocity of water through the other parts of the perimeter. The result was a velocity gradient in the water flow flowing in the space between the head and the pool surface. The cleaning action of such water flow was greatest where the flow velocity was greatest. This means that the cleaning efficiency of the head was greatest where the distance from the suction port to the perimeter of the head was shortest, and decreased rapidly as that distance increased to other parts of the head. In other words, the known rigid and flexible vacuum heads very definitely do not have uniform cleaning efficiency over their area.
The variation in cleaning efficiency of pool vacuum heads over their areas heretofore has been recognized and addressed in a nominal way. Shallow ribs have been formed in the undersides of various cleaner heads in various ways and arrangements in an effort to better direct the flow of water to the suction port of a head after it has entered at all places around its perimeter into the space between the head and the pool surface. The improvements provided by such ribs have been relatively small.
Therefore, the present state of wheeled vacuum heads for swimming pools is that they have greatest cleaning effect at their mid-length where the suction port to the suction hose opens to the underwise of the head body, and the cleaning effect decreases with distance along the heads on either side of the suction ports. The same conditions exist in the cleaning heads of suction-type automatic pool cleaners which move over pool floors at random in response to hydraulic forces applied to them.
A need exists for a wheeled vacuum cleaner head, useful to clean submerged surfaces of swimming pools and the like, in which the cleaning action of the head is substantially uniform along the length of the head and is not concentrated in the portion of the head closest to the suction port.
It is also known to manufacture and to market very long flexible wheeled swimming pool vacuum heads which have plural, usually two, suction ports through their bodies. These devices are marketed principally to professional pool cleaners and technicians whose economic objective is to clean as many pools per day as possible. Such long heads include a manifold tube connected between the several suction ports defined by the head and to which a single suction hose is connected in use for applying suction via the several suction ports to the space between the head and a surface being cleaned. In all other material respects, these long heads are like those described above. Examples of these long heads are found in the Rainbow Plastics Model 207 and Model 215 vacuum heads. Such long vacuum heads also present the need identified above.